1. Field of the Invention
The present invention relates to the non operative or orthotic treatment of scoliotic deformities and, more specifically, relates to a series of different orthoses that provide active corrective forces of derotation associated with kyphosing and/or lordosing forces on the trunk to provide a three dimensional (3-D) correction of scoliotic deformities, while still allowing complete or partial mobility of the trunk.
2. Description of the Prior Art
Scoliosis is a complex 3-D deformation of the trunk, spine and rib cage which involves "twisting" or rotation of the spine and rib cage in the transverse plane as well as lateral deviation of trunk in the frontal plane and usually a decrease of the normal curves in the sagittal plane. The most prevalent type is idiopathic scoliosis which affects 2 to 3% of the adolescent population. The harmful effects of spinal deformities have been recognized since antiquity, and although orthoses have been used in the treatment of scoliosis for centuries, an effective and widely recognized nonoperative method of treatment appeared only in 1945 with the advent of the Milwaukee brace, a description of which appears in the article entitled "Orthotic Treatment of Pediatric Spinal Disorders and Diseases" written by Labelle and Dansereau in "Spine: State of the Art Reviews", Vol. 4, No. 1, January 1990, pages 239-251. Orthotic management of spinal deformities is, therefore, a relatively new science still in evolution, explaining the rather large number of designs and materials that have appeared since the late 1960s.
An orthosis is an external orthopedic appliance used to control motion of body segments. The ideal orthosis for a spinal deformity should be able to restore the spine and rib cage to its normal alignment at the end of treatment. It should be lightweight, allow normal activities, be socially acceptable for the patient, and should not interfere with normal growth and development. These goals have not yet been fully achieved.
Before considering current orthoses in more detail, some general observations that apply to all braces need further discussion and should be kept in mind.
At present, there is no clear scientific proof of the validity of brace treatment, but there is strong clinical evidence to support it. Many publications have reported definite, positive, short- and long-term effects of bracing in idiopathic scoliosis, but they are retrospective case series without concurrent controls and are subject to many biases and methodological flaws.
The reported effects of bracing are remarkably similar in the literature. A curve improvement of 30 to 50% can usually be expected during brace wear, followed by a progressive loss of correction during weaning, with an eventual return to the prebrace measurement at follow-up. Success of brace treatment is thus limited to arrest of progression.
Braces work by the external application of a physical force at various locations on the thorax, spine, or pelvic girdle, and/or by active stimulation of corrective muscle contraction. The exact mode of action is not clearly understood, and the effect of bracing in the transverse and sagittal planes is poorly documented.
The usual indications for orthotic prescription include moderate curves between 20.degree. to 40.degree. in the skeletally immature. Braces have been usually worn on a full-time basis for periods varying from months to years, until skeletal maturity is reached, based on the premise that further progression will not occur at the end of growth.
There is no scientific proof or clinical evidence to support the use of physical therapy, intermittent traction, exercise, or manipulation as independently useful measures in the nonoperative treatment of spinal deformities.
The nomenclature developed in 1973 by the Task Force on Standardization of Orthotics Terminology is now widely accepted and is based on the joints or segments of the body encompassed. Two categories are of importance: CTLSO (cervical- thoracic-lumbar-sacral orthosis) and TLSO (thoracic- lumbar-sacral orthosis).
As progressive scoliotic deformities in adolescents may require treatment by a brace, various types of braces have been proposed in the past 50 years. In North America, one of the earliest type, still in use today, is the aforementioned Milwaukee brace (CTLSO) which consists of a molded plastic pelvic girdle, two metal uprights in the back and one upright in the front, all of which are adjustable. A neck ring with a throat pad is connected to the cephalic portion of the uprights. The brace works mostly by passive corrective lateral forces and longitudinal distraction by the neck ring, and is bulky and visible under the clothes so that compliance in the adolescent population is fairly low.
The Milwaukee brace was replaced in the early '70s by the Boston brace system (TLSO) which is described in the aforementioned Labelle et al. article and also in "Indications de la gymnastique, des procedes orthopediques et de la chirurgie dans les scolioses idiopathiques" written by Faucon et al. in the "Gazette Medicale de France", No. 3, Mar. 10 1965, pages 2-11. The Boston brace characterized by a series of prefabricated polypropylene molds which open from the back and are designed to firmly grip the pelvis and thorax to provide correction by passive forces with a three-point pressure principle and by the contact fit of the brace.
Many other orthotic devices (TLSO) made of rigid thermoplastic materials (such as the DuPont jacket, the Miami TLSO, the Newington brace, etc.) have also been designed as similar rigid torso-enveloping shells, but differ from the Boston brace in that they are usually custom fabricated from a positive mold of the patient taken supine on a traction table and that they work mostly by total trunk contact passive forces. Descriptions of the Dupont jacket appear in the aforementioned Labelle et al. reference and also in the article entitled "Treatment of Idiopathic Scoliosis with the Wilmington Brace" written by Bassett et al. in "The Journal of Bone and Joint Surgery, Incorporated", 68A, No. 4, April 1986, pages 602-605. The Miami TLSO is described in the aforementioned Labelle et al. article and also in "Miami TLSO in the Management of Scoliosis: Preliminary Results in 100 Cases" written by McCollough, III, et al. in the "Journal of Pediatric Orthopedics", Vol. 1, No. 2, 1981, pages 141-152. The Newington brace is also described in the Labelle et al. reference as well as in "The Thoracic Suspension Orthosis" written by Drennan et al. in the "Clinical Orthopaedics and Related Research", No. 139, March-April 1979, pages 33-39.
A dynamic orthotic device (U.S. Pat. No. 4,202,327 issued on May 13, 1980 to Glancy) has been claimed by Glancy to correct scoliotic deformities by means of a rigid torso enveloping shell with precut shell segments hinged to the rigid shell at one end and connected by an elastic strap to the rigid shell at the other end to provide a dynamic horizontal transverse pressure in a scoliotic deformity.
More recently, the Charleston bending brace (U.S. Pat. No. 4,688,558 issued on Aug. 25, 1987 to Hooper, Jr. et al.) has been introduced: it consists also of a rigid custom fabricated total contact plastic jacket but it is molded supine with a straight lateral unbending force at the apex of the scoliotic curve. It is designed for night time bracing only, contrary to previous orthoses.
In Europe, the Lyonese brace (TLSO) is a rigid three and four valve orthosis made of custom fitted "plexi-dur" and aluminum materials and works by three or four point pressures applied laterally to the scoliotic deformities. The Lyonese brace is mentioned in the aforementioned Labelle et al. and McCollough articles. From this brace, a lighter version of the Lyonese brace called the Olympe has been recently developed: it is claimed to combine part of the Lyonese brace for support and rigidity, and part of the elastic brace of "Corset Toile de St-Etienne" to make it lighter and more easily tolerable.
Another recent development is the 3-D brace (U.S. Pat. No. 5,012,798 issued on May 7, 1991 to Graf et al.), a rigid orthosis which consists of a molded plastic pelvic girdle connected to two plastic hands by two elastically semi-rigid lateral supports that can be put out of shape. 3-D correction is said to be achieved during the inspiratory phase of the respiratory cycle when the brace forces reduction by opposing the expansion of the thoracic cage.
All the aforementioned braces are partly or completely rigid thereby inhibiting completely the normal movements of the thoracic and lumbar spine in flexion, extension and lateral bending. These braces are also bulky and for these reasons used mostly for moderate or severe deformities. Furthermore, with all current orthoses, there is only one basic design available to correct any degree of curve severity of stiffness even if there are mild, moderate or severe curves that are of varying degree of stiffness.